Companies in the oil and natural gas industry often use metering pumps to transfer fluids in harsh or remote locations. Many such pumps provide precise fluid dispensation by converting rotational motion delivered from a solar or AC grid powered motor to linear reciprocating motion in a piston. During a complete piston stroke, fluid is both drawn into the pump and discharged from the pump at a particular rate depending on piston displacement and rotation cycle time. Frictional forces and side loading acting within these pumps can cause both wear on pump components and operational inefficiency. Wear often decreases the life of these components and results in failure modes requiring downtime for repair. Pump inefficiency can increase demand load on the sources powering the pump. Minimizing component wear and pump inefficiency can thus reduce end-user costs.
While metering pumps typically drive a piston using a cam, many use either spring or carriage assemblies to return the piston. In spring assemblies, the spring force used to return the piston can act against it during the discharge stroke, causing higher energy penalties and additional wear on the pump head and rotary components. Carriage assemblies, by contrast, can require a number of additional parts to facilitate piston return. Using additional parts often provides more wear points and thus more potential failure modes.
Metering pump pistons generally reciprocate within a channel. Friction between the piston and the rotary components attached to the motor can impart a slight rotation on the piston. This rotation in turn causes side loading on the parts forming the piston channel. Side loading on these parts decreases the life thereof and can necessitate pump repair. It can also force end-users to purchase more replacement parts.